توليد مثل و بلوغ جنسي كفال طلايي Liza aurata Risso, 1810 در آب هاي ايراني درياي خزر

Reproduction and maturity of golden grey mullet (Liza aurata Risso, 1810) in Iranian waters of the Caspian Sea

Mullets are one of the dominant fishes in the catch composition in the Southern coasts of the Caspian Sea and after Kutum have a worthy roll in production of marine proteins and incomings in three Northern provinces of Iran. Golden grey mullet constitute about 95% of the species composition of mullet in the catch in the last decade. In order to determine the reproduction period, the peak time of spawning and LM50% this study was carried out from January 2007 to December 2007 randomly from 53 beach seines in the coastal waters of the Caspian Sea (Mazandaran province). The mesh size used in this study was 30, 33 mm in the fishing season and 8 mm in the cod end from March to October. Mean fork length, total weight and age of grey golden mullet were estimated respectively 32.8±5.71 Cm, 402.8±322.4 g and 4.3±1.42 year. Maturity age of the male and female were identified respectively 3.7 and 4.8 years. On the base of GSI and apparent observation of sex organs, the spawning period was begun from the beginning of Mehr to Azar and the peak of spawning activity was determine in first half of Aban. Absolute fecundity was calculated 740259.4±75426.1 and it was increased by length, weight and age growth. LM50o/o (length of maturity) was calculated 26.6 Cm (fork length). The results showed overlap between the peak of spawning activity and the beginning time of fishing season. Also, the length of maturity decreased about 1.4 Cm and they were matured sooner than past in the Caspian Sea.